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National Geographic NG90EQ Instructions And Owner's Manual

Maksutov-cassegrain telescope
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NG90EQ
Maksutov-Cassegrain
Telescope
Instructions
and
Owner's Manual

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Summary of Contents for National Geographic NG90EQ

  • Page 1 NG90EQ Maksutov-Cassegrain Telescope Instructions Owner’s Manual...
  • Page 2 C. Slow-motion control knobs D. 9mm eyepiece E. 25mm eyepiece NEVER aim your telescope at the sun or even close to the sun! Instant and irreversible damage can occur, Do not let children use any telescope without adult supervision. G. 3X Barlow lens H.
  • Page 3 As a terrestrial (land) telescope, the NG90EQ delivers great views of mountains, valleys, and many other features of the world around us. You can also use the NG90EQ to study animals and landscapes at a distance. To obtain the best performance from your telescope, please read this manual carefully and completely.
  • Page 4 2) Each aluminum tripod leg can extend to almost double its closed length. This enables the height of the telescope to be adjusted to comfortably suit most users. Each leg is equipped with a locking knob that can be loosened to perform this adjustment and then retightened.
  • Page 5 (Fig. 2) 5) The main optical unit is attached to the equatorial mount with a black cast metal mounting plate. This mounting plate has four chromed screws mounted in it. Remove all four screws. The mounting plate has one smooth face and one face with small ridges.
  • Page 6 7) The counterweight balances your telescope and makes it easy to adjust and position. Hold the counterweight in your hand so you can see through the hole in the weight. Make sure that the black tightening knob on the counterweight is facing down.

  • Page 7: Finder Scope Alignment

    (Fig. 16) FINDER SCOPE ALIGNMENT Since a telescope has a narrow field of view by design, it can be challenging to locate a particular star or planet. For this reason the telescope is fitted with a low-power, wide- field miniature telescope called a finder scope. Always use your finder scope to locate the object you want to view FIRST.
  • Page 8 Your telescope is equipped with an advanced equatorial mount. This type of mount moves the main optical tube in a circular fashion. This is very important because it means that you can set up the NG90EQ to conveniently compensate for the rotation of the Earth.
  • Page 9 (Fig. 22) A WORD ABOUT THE TWO EYEPIECE PORTS The NG90EQ is fitted with two eyepiece ports. The top port generally is used for astronomical viewing. The view you see will be right side up, but will be laterally reversed, like looking in a mirror. This is normal, and is of no consequence.

  • Page 10: About Magnification

    Higher magnification powers can be achieved by using the included 3X Barlow lens. The 3X Barlow lens is inserted between the telescope and the eyepiece. In Fig. 20 it is shown being used at the rear eyepiece port. It can be used at either eyepiece port.
  • Page 11 10 mm of objective lens diameter. Magnification of around 265X or less is ideal for a telescope with a 90-mm diameter objective lens and is best for observing most celestial objects. A lower magnification power and a wider field of view are advisable for the observation of galaxies and nebulae.

  • Page 12: Using Your Telescope For Terrestrial Viewing

    You can now control the vertical motion of the telescope by loosening the right ascension tightening knob (See Fig. 23), and you can adjust the horizontal movement by loosening the azimuth locking knob (See Fig.
  • Page 13 If, after several attempts, you cannot remove the particles, take the telescope to an optical professional for cleaning. If you keep the dust caps on your telescope when it is not in use and avoid handling the lenses or mirrors, only minimal optical maintenance of your telescope should be required.

  • Page 14: Frequently Asked Questions

    The planet and its rings appear pale yellow. The major division in the rings, the Cassini division, is possible to see if you keep the telescope firmly in position. Uranus and Neptune are the last of the solar system’s gas giants. They do not provide as spectacular a sight as Jupiter or Saturn, but are nonetheless rewarding to see.
  • Page 15 National Geographic’s net proceeds support vital exploration, conservation, research, and education programs.  2003 National Geographic Society. NATIONAL GEOGRAPHIC and Yellow Border are trademarks of National Geographic Society. All rights reserved. Experience the National Geographic Channel. Call your cable or satellite provider for availability.